Wow! Can't believe I didn't realise that. It is definitely a prohibited barrel length in revolver form.that barrel looks shorter than 4.13in to me, more like 3"
at least one got imported, i remember the thread on it
June 2010: On request, custom made longer barrels for two rare MATEBA revolvers. Made with 79 degree target crowns, tight cylinder to barrel gap & 11 degree forcing cones. Note: pictures taken before bluing and final installation.